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I have a 2001 BMW 740i E38 w/Sport Pkg, bought used w/32000mi in 2006. I changed the oil for the 1st time at 36,000mi when the indicator light came on. My Performance Specialist Mechanic told me to use AMSOIL 100% Synthetic 0W-30W Motor oil (a 25,000 mi oil) the best available, and while I am at it to also change my trans fluid and rear differential oil using AMSOIL Synthetic ATF and AMSOIL 75W-90W severe gear oil. He said change the rear diff. oil every 50,000 mi. He changed the oil and filter and differential oil and told me to change the canister oil filter every 7,500 mi, which is easy. After he was done he said go to a parking lot about a block away and do some tight figure eights at normal slow speed to get the new gear oil to the ends of your axles. I then went to a well known transmission shop, at his recommendation, and they ordered a trans kit (gasket and filter) for my E38, dropped the pan and about 5 1/2 qts flowed out. They said my old fluid was just beginning to turn to varnish, originally yellow in color, and no sludge had formed "yet". I gave them 5 1/2 qts of AMSOIL ATF, red in color, and they replenished the trans with it and installed the new trans filter and gasket, replacing the pan. They said do this every 30,000 mi and sooner is not necessary. I immediately noticed my engine is quieter and that my transmission shifts smoother and more positively. My mechanic said that AMSOIL Synthetic ATF has superior high and low temperature performance and is highly resistant to thermal breakdown and oxidation, protects from damaging sludge and varnish twice as long as regular ATF. He said BMW will tell you not to change the transmission fluid for life and that is because there is a 50,000 mi warranty and when that expires their responsibility is over. Your plates inside the trans are bathed in ATF fluid so you need to change the fluid to keep the plates from wearing prematurely. Using AMSOIL ATF will make your trans last much, much longer than the 150,000 to 160,000 mi that the dealer indicates. Those of you that are afraid to change your trans fluid, as I read on some of the forums, because you are told not to for the life of the transmission, don't be it is the best thing you could do for your trans. I now have 105,000 mi on my BMW and my engine is much quieter and cleaner and my indicator lights do not come on now until about 21,000 mi, whereas, before using BMW Synthetic oil the indicator light would come on at the standard 15,000 mi's and my dip stick, without adding any new oil, shows the oil level still at the "top like it never burned a drop". After three ATF changes you will just about have changed all your trans fluid to new AMSOIL Synthetic ATF. Please tell me your comments!

Last edited by R Lettelier; 10-14-2011 at 11:33 PM.
Reason: Tell people to reply

Thanks for the info. I just bought a mint condition 2001 740i with 146,000 miles, I have owned BMW's and SL Mercedes since 1976 and my SL320 was just stolen so I went back to the Bimmer. How expensive is getting the trans rear differential oil and gasket, filter cost? Thanks Clint

To answer your question about the cost of the trans and differential fluid changes. When I brought my 2001 BMW 740i E38 to the trans shop, I first called them so they would order a transmission service kit specifically for my car so it would be there when I went to get my Trans fluid changed. When I actually went there I brought my own AMSOIL ATF and my own AMSOIL differential fluid, therefore they would have everything when they started the fluid changes.

Since your car has 146,000 mi on it your clutch plates could already be worn, unless the previous owner changed the trans fluid. I would suggest doing a partial change which is very simple and the least expensive The transmission pan on the bottom of the trans is removed and also the gasket and filter and about 5 !/2 Qts of trans fluid will flow out, which is about half of the total trans capacity. A new gasket and filter are installed and the pan is bolted back on. Now, if the old trans fluid that flows out and discarded is "yellow" in color, then it is most likely the original BMW Fluid. If it is "red", then it is newer fluid and has been changed at least once, this is good. Then about 5 1/2 qts of the new fluid is filled. Now, just by doing that you have replace about half of the total fill, that's fine. Do this every 30,000 mi.

The differential fluid has to pumped out of the differential and about 1 and 1/4 qts will be put back in. Do this change every 50,000 mi. After that, your done. When you drive away you might want to immediately drive into a half way vacant parking lot and do about 3 or 4 figure 8's slowly just to get the diff oil back into the axles, just to be safe.

Total cost to me for doing those two changes including labor and tax was $230.00. Well worth it!

You might want to visit www.AMSOIL.com and enter your car info. and all the specs for your car will come up on the next screen. I think AMSOIL has the best products.